The present invention relates to an apparatus and method for transferring at high speed a program stored in an external storage device and, more particularly, to an apparatus and method for loading a program stored in an external storage device connected to a first bus to a second memory connected to a second bus.
A conventional program transfer method of this type will be described below with reference to FIG. 1. The portion above the broken line in FIG. 1 corresponds to a host device, and the portion therebelow corresponds to an interface device. The interface device controls, e.g., a LAN (Local Area Network). Program data executed by the interface device is stored in disk device 6 of the host device. Therefore, upon operation of the interface device, program data must be loaded from the host device to the interface device. When the program data stored in disk device 6 is transferred to interface memory 2, host CPU 5 reads out the program data from disk device 6 and first loads the data in host memory 1. Thereafter, host CPU 5 sets the destination address for interface memory 2 in address register 3. Host CPU 5 then reads out the program data in a predetermined unit, and stores the data in data register 4. When the program data and the destination address are set, interface CPU 7 reads out the destination address from address register 3 and the program data from data register 4, respectively, and loads the program data at the destination address of interface memory 2.
However, in the conventional program transfer method, the program data read out from disk device 6 is temporarily loaded in host memory 1, and is then transferred from host memory 1 to interface memory 2. Therefore, program transfer requires much transfer time.